1.Comparison of Wild and Cultivated Bupleurum scorzonerifolium Based on Traditional Quality Evaluation
Changsheng YUAN ; Feng ZHOU ; Xingyu LIU ; Yu SHI ; Yihan WANG ; Huaizhu LI ; Yongliang LI ; Shan GUAN ; Huaizhong GAO ; Yanmeng LIU ; Zhilai ZHAN
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(5):203-214
ObjectiveTo characterize the quality differences among different germplasm and introduced varieties of Bupleurum scorzonerifolium roots(BSR), and explore the underlying molecular mechanisms, providing a basis for high-quality production and quality control. MethodsWild BSR from Yulin(YLW) served as the quality reference, we conducted comparative analysis among YLW, locally domesticated wild germplasm in Yulin(YLC3), Daqing germplasm introduced and cultivated in Yulin(YLDQC3), and locally cultivated germplasm in Daqing(DQC3). A combination of traditional pharmacognostic methods and modern multi-omics analyses was employed, including macroscopic traits(appearance, odor), microscopic features(proportions of cork, phloem, xylem), cell wall component contents(hemicellulose, cellulose, lignin), carbohydrate contents(starch, water-soluble polysaccharides), marker compound contents(ethanol-soluble extracts, total saponins, liposoluble extracts, and saikosaponins A, B2, C, D), metabolomics, and transcriptomics, in order to systematically characterize quality differences and investigate molecular mechanisms among these samples. ResultsMacroscopically, Yulin-produced BSR(YLW, YLC3, YLDQC3) exhibited significantly greater weight, length, and upper and middle diameters than Daqing-produced BSR(DQC3). Odor-wise, YLW and YLC3 had a a fragrance taste, YLDQC3 had a rancid oil odor, and DQC3 had a sweet and fragrant taste. Microscopically, Yulin germplasm(YLW, YLC3) and Daqing germplasm(YLDQC3, DQC3) shared similar structural features, respectively. However, Yulin germplasm showed significantly higher proportions of cork and phloem, as well as stronger xylem vessel staining intensity compared to Daqing germplasm. Regarding various component contents, Yulin germplasm contained significantly higher levels of ethanol-soluble extracts, total saponins, and saikosaponins A, B2, C, D, while Daqing germplasm had significantly higher levels of hemicellulose, starch, and liposoluble extracts. After introduction to Yulin, the Daqing germplasm(YLDQC3) showed increased starch, water-soluble polysaccharides and liposoluble extracts contents, decreased cell wall component content, but no significant difference in other component contents. Metabolomics revealed that saponins and terpenes accumulated significantly in Yulin germplasm, while alcohols and aldehydes accumulated predominantly in Daqing germplasm. Transcriptomics indicated similar gene expression patterns within the same germplasm but specificity between different germplasms. Integrative metabolomic-transcriptomic analysis identified 145 potential key genes associated with the saikosaponin biosynthesis pathway, including one acetyl-coenzyme A(CoA) acetyltransferase gene(ACAT), one 3-hydroxy-3-methylglutaryl-coenzyme A synthase gene(HMGS), two hydroxymethylglutaryl-CoA(HMG-CoA) reductase genes(HMG), one phosphomevalonate kinase gene(PMK), one 1-deoxy-D-xylose-5-phosphate synthase gene(CLA), one hydroxymethylbuten-1-aldol synthase gene(HDR), two farnesyl pyrophosphate synthase genes(FPPS), one squalene synthase gene(SQS), one β-amyrin synthase gene(BAS), 102 cytochrome P450(CYP450) gene family members, and 32 uridine diphosphate-glucuronosyltransferase(UGT) gene family members. ConclusionAmong the three cultivated types, YLC3 most closely resembles YLW in appearance, microscopic features, contents of major bioactive constituents, metabolomic and transcriptomic profiles. Yulin germplasm exhibits superior saponin synthesis capability compared to Daqing germplasm, and Yulin region is more suitable for the growth of B. scorzonerifolium. Based on these findings, it is recommended that artificial cultivation in northern Shaanxi and similar regions utilize the local Yulin germplasm source cultivated for at least three years.
2.Comparison of Wild and Cultivated Polygalae Radix Based on Traditional Quality Evaluation
Yihan WANG ; Yanmeng LIU ; Huaizhu LI ; Yongliang LI ; Shan GUAN ; Zhilai ZHAN
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(5):215-224
ObjectiveBased on the traditional quality evaluation methods summarized in previous dynasties, this paper systematically contrasted the quality differences between wild Polygalae Radix(WPR) and cultivated Polygalae Radix(CPR) from the aspects of character, microscope and chemical composition by modern scientific and technological means, providing a basis for high-quality production and quality control. MethodsCPR and local WPR in Yulin city, Shaanxi province from 1 to 6 years were collected, and a systematic comparative analysis was conducted using traditional pharmacognosy research methods combined with modern multi-omics analysis techniques, including character traits(length, weight, diameter), cross-sectional microscopic features(proportions of cork, phloem, xylem, etc), cell wall component content(hemicellulose, cellulose, lignin), extracts content(water-soluble extract and alcohol-soluble extract), carbohydrate content(starch, water-soluble polysaccharides), contents of total flavonoids, total saponins and specific marker compounds(3,6′-disinapoyl sucrose, polygalaxanthone Ⅲ, tenuifoliside A, tenuifoliside C, sibiricose A5 and A6) and other indexes. Ultra-high performance liquid chromatography-quadrupole-time-of-flight mass spectrometry(UPLC-Q-TOF-MS) was employed to conduct comparative analysis of secondary metabolites in WPR and CPR, and multivariate statistical analysis such as principal component analysis(PCA) and orthogonal partial least squares-discriminant analysis(OPLS-DA) were combined to screen the key differential components of them. ResultsIn terms of appearance, there were significant differences between WPR and CPR. The characteristics of WPR conformed to the "thick wrinkles on the epidermis" recorded in ancient books, featuring a wrinkled surface and grayish-brown appearance. However, CPR had a finer texture and a yellowish white appearance, with weight, length, and diameter increasing with longer cultivation periods. In terms of microscopy, WPR exhibited a thick cork layer with fissures in the phloem, whereas CPR had a thinner cork layer with uniformly arranged cork cells. Younger PR specimens showed numerous phloem fissures in cross-sections, while older specimens display progressively denser arrangements of phloem parenchyma cells. In terms of the contents of various major components, the contents of water-soluble extract, starch and total saponins in WPR were inversely proportional to the root diameter, while the contents of water-soluble extract, water-soluble polysaccharides and total saponins in CPR decreased with the increase of planting years. The content of xanthones in WPR was significantly higher than that of CPR, while the contents of other major components showed no significant change pattern. Among the six indicator components, the average content of sibiricose A5 in WPR was significantly higher than that of CPR, followed by slightly higher content of tenuifoliside A. In CPR, the relative content of 3,6′-disinapoyl sucrose and tenuifoliside A was the highest. The former showed an increase in volatility with increasing cultivation years, while the latter showed a decrease in volatility. The results of differential compound analysis based on UPLC-Q-TOF-MS showed that there were significant differences in metabolites between WPR and CPR samples. Among them, the seven compounds with the largest differences among WPR samples of different thicknesses were polygalasaponins, and for CPR with different planting years, the main differential compounds were oligosaccharide esters. ConclusionThere are differences between WPR and CPR in character, microscopic structure and chemical composition, and some components are inversely proportional with the increase of diameter and cultivation duration due to the distribution characteristics. However, the longer the cultivation years of PR, the closer it is to the "thick wrinkles on the epidermis" of WPR, which has been respected by generations. It is suggested that this traditional character combined with modern component contents should be used as the index of artificial cultivation and quality control of PR.
3.Deoxyshikonin inhibits the proliferation, invasion, and tumor immune microenvironment in breast cancer cells by inactivating the PI3K/AKT/NF-κB pathway
Shaolan YU ; Dayan NIE ; Xia GUAN ; Lihui SHAN ; Xun YU ; Sanjun GUO
Nutrition Research and Practice 2026;20(2):167-181
BACKGROUND/OBJECTIVES:
Deoxyshikonin (DSK) has been reported to inhibit tumor growth in various types of cancers, but its roles and action mechanisms in breast cancer (BC) are unclear. This study examined the anti-cancer function and mechanism of DSK in BC.MATERIALS/METHODS: MDA-MB-231 and BT549, human BC cells, were used. The cell viability and apoptosis levels were examined using Cell Counting Kit-8 experiments and flow cytometry, respectively. The expression of apoptosis-related factors (Ki-67, Bax, and Bcl-2), CD206, CD168, and proteins involved in the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)uclear factor (NF)-κB pathway was evaluated by Western blot analysis. The cell invasion ability was determined using the Transwell experiment. The levels of interleukin (IL)-10 and transforming growth factor (TGF)-β were detected using an enzyme-linked immunosorbent assay. The in vivo functions of DSK were assessed using a xenograft mouse model.
RESULTS:
DSK inhibited cell proliferation, enhanced cell apoptosis, and reduced the cell invasion of MDA-MB-231 and BT549 cells. DSK also reduced the levels of CD206 and CD168 proteins, as well as IL-10 and TGF-β in phorbol 12-myristate 13-acetate-induced THP-1 cells.DSK downregulated the expression of the phosphorylated (p)-PI3K, p-AKT, and p-NF-κB proteins in cells. These effects were reversed by 740 Y-P (PI3K/AKT activator). In addition, DSK significantly reduced the tumor volume and weight in a xenograft mouse model. DSK increased the level of cell apoptosis and decreased the expression of Ki-67 and CD206 in subcutaneous tumor tissue. DSK also inactivated the PI3K/AKT/NF-κB pathway proteins.
CONCLUSION
DSK inhibits the proliferation, invasion, and tumor immune microenvironment of BC cells by inactivating the PI3K/AKT/NF-κB pathway, indicating that DSK may be a potential therapeutic option for BC treatment.
4.Inhibitory Role of Family with Sequence Similarity 162 Member A in the Fibrotic Phenotypes of Cardiac Fibroblasts
Chuanmeng ZHOU ; Peiying GUAN ; Rushi WU ; Jiening ZHU ; Juntao FANG ; Yupeng LIU ; Xianhong FANG ; Zhixin SHAN
Journal of Sun Yat-sen University(Medical Sciences) 2026;47(2):238-250
ObjectiveTo investigate the expression of family with sequence similarity 162 member A (Fam162a), a mitochondrial inner membrane protein, in the fibrosis of cardiac fibroblasts and its regulatory role in modulating the fibrotic phenotype of cardiac fibroblasts. MethodsFam162a protein expression was detected in myocardial samples from patients with heart failure (HF) and mice with transverse aortic constriction (TAC)-induced myocardial remodeling. Primary neonatal mouse cardiac fibroblasts (mCFs) were isolated and cultured, and a cell model of angiotensin Ⅱ (Ang Ⅱ)-induced myocardial fibrosis was established to determine Fam162a protein expression. Recombinant adenovirus was used to mediate Fam162a overexpression, while small interfering RNA (si-RNA) was employed for Fam162a knockdown. Western blot was performed to detect the expression of fibrosis-related proteins, including COL1A1, COL3A1, and α-SMA. EdU staining assay was used to evaluate cell proliferation capacity, and scratch assay combined with Transwell assay was conducted to assess cell migration ability. Immunofluorescence assay was applied to measure mitochondrial membrane potential for reflecting mitochondrial dysfunction; reactive oxygen species (ROS) detection was performed to evaluate cellular oxidative stress status; MitoSox assay was used to reflect the degree of mitochondrial oxidative damage; and ATP detection was conducted to assess the overall cellular energy metabolism. ResultsFam162a expression was significantly downregulated in the myocardium of HF patients and TAC mice, and Ang Ⅱ-treated mCFs, accompanied by increased expression of COL1A1, COL3A1, and α-SMA (all P<0.05). Adenovirus-mediated overexpression of Fam162a significantly inhibited Ang Ⅱ-induced upregulation of fibrosis-related genes, as well as cell proliferation and migration. Accordingly, silencing Fam162a aggravated the fibrotic phenotypes of mCFs treated with Ang II. Further studies revealed that the inhibitory effect of Fam162a overexpression on Ang Ⅱ-induced fibrotic phenotype was suppressed following the addition of rotenone (a mitochondrial oxidative respiratory chain inhibitor), which was accompanied by mitochondrial membrane potential depolarization, excessive ROS production, and insufficient ATP generation. ConclusionFam162a exerts its inhibitory effect on the fibrotic phenotype of cardiac fibroblasts by maintaining mitochondrial membrane potential, promoting ATP production, reducing reactive oxygen species (ROS) generation, and suppressing Smad3 signaling activation.
5.Guideline for Adult Weight Management in China
Weiqing WANG ; Qin WAN ; Jianhua MA ; Guang WANG ; Yufan WANG ; Guixia WANG ; Yongquan SHI ; Tingjun YE ; Xiaoguang SHI ; Jian KUANG ; Bo FENG ; Xiuyan FENG ; Guang NING ; Yiming MU ; Hongyu KUANG ; Xiaoping XING ; Chunli PIAO ; Xingbo CHENG ; Zhifeng CHENG ; Yufang BI ; Yan BI ; Wenshan LYU ; Dalong ZHU ; Cuiyan ZHU ; Wei ZHU ; Fei HUA ; Fei XIANG ; Shuang YAN ; Zilin SUN ; Yadong SUN ; Liqin SUN ; Luying SUN ; Li YAN ; Yanbing LI ; Hong LI ; Shu LI ; Ling LI ; Yiming LI ; Chenzhong LI ; Hua YANG ; Jinkui YANG ; Ling YANG ; Ying YANG ; Tao YANG ; Xiao YANG ; Xinhua XIAO ; Dan WU ; Jinsong KUANG ; Lanjie HE ; Wei GU ; Jie SHEN ; Yongfeng SONG ; Qiao ZHANG ; Hong ZHANG ; Yuwei ZHANG ; Junqing ZHANG ; Xianfeng ZHANG ; Miao ZHANG ; Yifei ZHANG ; Yingli LU ; Hong CHEN ; Li CHEN ; Bing CHEN ; Shihong CHEN ; Guiyan CHEN ; Haibing CHEN ; Lei CHEN ; Yanyan CHEN ; Genben CHEN ; Yikun ZHOU ; Xianghai ZHOU ; Qiang ZHOU ; Jiaqiang ZHOU ; Hongting ZHENG ; Zhongyan SHAN ; Jiajun ZHAO ; Dong ZHAO ; Ji HU ; Jiang HU ; Xinguo HOU ; Bimin SHI ; Tianpei HONG ; Mingxia YUAN ; Weibo XIA ; Xuejiang GU ; Yong XU ; Shuguang PANG ; Tianshu GAO ; Zuhua GAO ; Xiaohui GUO ; Hongyi CAO ; Mingfeng CAO ; Xiaopei CAO ; Jing MA ; Bin LU ; Zhen LIANG ; Jun LIANG ; Min LONG ; Yongde PENG ; Jin LU ; Hongyun LU ; Yan LU ; Chunping ZENG ; Binhong WEN ; Xueyong LOU ; Qingbo GUAN ; Lin LIAO ; Xin LIAO ; Ping XIONG ; Yaoming XUE
Chinese Journal of Endocrinology and Metabolism 2025;41(11):891-907
Body weight abnormalities, including overweight, obesity, and underweight, have become a dual public health challenge in Chinese adults: overweight and obesity lead to a variety of chronic complications, while underweight increases the risks of malnutrition, sarcopenia, and organ dysfunction. To systematically address these issues, multidisciplinary experts in endocrinology, sports science, nutrition, and psychiatry from various regions have held multiple weight management seminars. Based on the latest epidemiological data and clinical evidence, they expanded the guideline to include assessment and intervention strategies for underweight, in addition to the core content of obesity management. This guideline outlines the etiological mechanisms, evaluation methods, and multidimensional management strategies for overweight and obesity, covering key areas such as diagnosis and assessment, medical nutrition therapy, exercise prescription, pharmacological intervention, and psychological support. It is intended to provide a scientific and standardized approach to weight management across the adult population, aiming to curb the rising prevalence of obesity, mitigate complications associated with abnormal body weight, and improve nutritional status and overall quality of life.
6.Analysis of Tongue Image Features in Patients with Idiopathic Membranous Nephropathy at Different Risk Levels
Haiyu GUAN ; Siqiao TANG ; Ping LI ; Wenjun SHAN ; Xiaofan HONG ; Yue CAO ; Lihong YANG ; Kun BAO
Journal of Guangzhou University of Traditional Chinese Medicine 2025;42(1):9-17
Objective To analyze the correlation between tongue image features and the risk levels of disease in patients with idiopathic membranous nephropathy(IMN).Methods Based on IMN clinical research electronic data acquisition system,a cross-sectional study method was used to analyze the clinical diagnosis and treatment data of 135 IMN patients from Guangdong Provincial Hospital of Chinese Medicine.The patients were grouped according to the risk levels of disease,and then the correlation between the risk levels of disease and tongue image features was analyzed.During the description of tongue image features,TB is for tongue body,TC is for tongue coating,L is for luminance,a is for red-green axis,G is for the value of green,B is for the value of blue,and AUT is for the value of autocorrelation.Results The comparison of tongue image feature indicators of patients with different risk levels of IMN showed that:(1)the higher the level of disease risk of IMN patients,the greater the values of TB-L,TB-G and TB-B(P<0.05 or P<0.01).The values of tongue image indicator TB-a and TC-a of the patients with different risk levels of IMN were shown in decreasing sequence:low-risk group>high-risk group>middle-risk group>extremely-high-risk group(P<0.05).(2)Linear regression analysis showed that TB-L,TB-G,and TB-B were significantly increased in the high-risk group compared with those in the middle-and low-risk groups(P<0.05 or P<0.01),whereas there were no significant differences between the middle-risk group and low-risk group(P>0.05).(3)The results of correlation analysis showed that there was a positive correlation among most of the tongue image feature indicators(including TB-L,TB-G,TB-B,TB-AUT,TC-L,TC-G,and TC-B,etc.)and the risk level of disease,while TB-a was negatively correlated with the risk level of disease,and the differences were all statistically significant(P<0.05 or P<0.01).(4)All patients were treated with Chinese medicine and/or Chinese patent medicine,and 46.7%of patients were given hormones and immunosuppressants,and there was no statistically significant difference in the the use of hormones and immunosuppressants among various groups(P=0.637).Conclusion There is a correlation between the tongue image features of IMN patients and the risk level of disease,and the results will provide an objective reference for the assessment of illness state and traditional Chinese medicine(TCM)syndrome differentiation of IMN patients.With reference to the changes in the tongue image features,the illness state can be precisely identified,which is more accurate than the inspection of four diagnostic methods of TCM.
7.circHERC4_041 Inhibits the Fibrotic Phenotype of Cardiac Fibroblasts by Encoding Protein
Yuan GAO ; Chuan-Meng ZHOU ; Hua-Yan WU ; Ya WANG ; Ru-Shi WU ; Pei-Ying GUAN ; Jun-Tao FANG ; Jin-Dong XU ; Yu-Peng LIU ; Zhi-Qin HU ; Zhi-Xin SHAN
Chinese Journal of Biochemistry and Molecular Biology 2025;41(3):393-403
A mounting body of research suggests that circRNAs significantly contribute to the develop-ment of myocardial fibrosis.The microarray results of human circular RNA expression profile indicated that circHERC4_041 expression increased in the myocardium of patients with heart failure,RT-qPCR a-nalysis confirmed that the myocardial expression level of circHERC4_041 in individuals with heart failure were considerably elevated compared to that in healthy organ donors.Fluorescence in situ hybridization(FISH)confirmed that circHERC4_041 was abundant in the cytoplasm of human cardiomyocyte AC16.Overexpression of circHERC4_041 in mouse myocardial fibroblasts(mCFs)mediated by adenovirus in-hibited the expression of fibrosis-related proteins in mCFs.Experiments involving cell proliferation,wound healing,and Transwell assays demonstrated that overexpression of circHERC4_041 suppressed the growth and mobility of mCFs(P<0.001).Sequence analysis results suggested that circHERC4_041 con-tains potential ribosome entry sequence(IRES)and open reading frame(ORF).Western blot confirmed that circHERC4_041 could translate the 516 amino acid HERC4-516aa protein,which was mainly located in the cytoplasm of the cell.Cell functional experiments confirmed that circHERC4_041 inhibited the fi-brotic phenotype of mCFs by specifically translating HERC4-516aa(P<0.05).The specific interaction between HERC4-516aa and transglutaminase 2(TGM2)was confirmed by IP-MS screening and Co-IP i-dentification.Further results found that the degradation of TGM2 was promoted through proteasome path-way.The overexpression of TGM2 in mCFs facilitated by adenoviral vectors could counteract the suppres-sive effects of HERC4-516aa on the fibrotic phenotype of mCFs.Therefore,this study confirmed that the HERC4-516aa protein translated by circHERC4_041 can specifically bind to TGM2 to inhibit the fibrotic phenotype of myocardial fibroblasts.
8.Analysis of causes and countermeasures for forensic clinical judicial expertise errors involving medical imaging
Lina GUAN ; He YAN ; Qi DU ; Shenglan LI ; Zhuo ZHANG ; Jianheng AO ; Shan PU ; Yunlan LI ; Shijun HONG
Chinese Journal of Forensic Medicine 2025;40(2):156-162
The accuracy of medical imaging diagnosis will directly impact the clinical forensic evaluation's scientific validity and objectivity.This study systematically analyzed the primary causes of misdiagnosis and missed diagnosis in imaging examinations,focusing on representative cases,including rib fractures,traumatic subarachnoid hemorrhage,joint injuries with ligament damage,nasal fractures,congenital skeletal variations,and epiphyseal injuries.Key contributing factors encompassed limitation of imaging technologies,the insufficient interpretive experience of examiners,the complexity of injury mechanisms,and inadequate post-traumatic dynamic imaging follow-up.To address these issues,improvement strategies are proposed,which were establishing standardized imaging review protocols,implementing multimodal imaging approaches,rigorous evaluation of original imaging data,and enhancing professional knowledge regarding anatomical variations and injury differentiation.These measures aim to elevate the quality of forensic imaging diagnosis,providing more precise and reliable strategies for forensic clinical identifications.
9.Adverse reactions to Erwinia asparaginase and pegaspargase in the treatment of acute lymphoblastic leukemia in children
Shan HUANG ; Yujie GUAN ; Lili SONG ; Lihuan SHI ; Wei LIU
Journal of China Medical University 2025;54(7):608-612
Objective To compare the adverse reactions to pegasparaginase(PEG-ASP)and Erwiniaasparaginase(ASP)in the treat-ment of pediatric acute lymphoblastic leukemia(ALL)and to provide clinical guidance for treatment.Methods A total of 13 patients who were switched from PEG-ASP to Erwinia ASP due to allergic reactions during the induction phase of ALL treatment at the Depart-ment of Hematology and Oncology,Children's Hospital Affiliated of Zhengzhou University between February 2022 and February 2023 were selected as the case group.A control group of 26 patients treated with PEG-ASP and matched for sex at a ratio of 1∶2 was also selected.Pre-and post-treatment coagulation function,blood biochemistry,blood ammonia level,and gastrointestinal reactions were compared between the groups.Results There were no significant differences in AST,TB,UB,TC,TG,AMY,UN,Cr,APTT,and Fbg levels between the two groups,pre-and post-treatment.However,ALT,GGT,BB,and Glu levels were higher in the control group,whereas albumin was lower than in the case group(P<0.05).Both groups had an increased post-treatment blood ammonia level(P<0.05),with significantly a higher level observed in the case group than in the control group(P<0.001).No significant differences in adverse gastro-intestinal reactions were observed between the two groups.Conclusion Erwinia ASP and PEG-ASP affected liver function in pediatric ALL re-induction therapy with minimal effects on coagulation and weaker gastrointestinal reaction.Erwinia ASP significantly affected the blood ammonia level,and both treatments caused mild gastrointestinal reactions.Regular blood ammonia monitoring,post Erwinia ASP treatment,is recommended.
10.Structural and Spatial Analysis of The Recognition Relationship Between Influenza A Virus Neuraminidase Antigenic Epitopes and Antibodies
Zheng ZHU ; Zheng-Shan CHEN ; Guan-Ying ZHANG ; Ting FANG ; Pu FAN ; Lei BI ; Yue CUI ; Ze-Ya LI ; Chun-Yi SU ; Xiang-Yang CHI ; Chang-Ming YU
Progress in Biochemistry and Biophysics 2025;52(4):957-969
ObjectiveThis study leverages structural data from antigen-antibody complexes of the influenza A virus neuraminidase (NA) protein to investigate the spatial recognition relationship between the antigenic epitopes and antibody paratopes. MethodsStructural data on NA protein antigen-antibody complexes were comprehensively collected from the SAbDab database, and processed to obtain the amino acid sequences and spatial distribution information on antigenic epitopes and corresponding antibody paratopes. Statistical analysis was conducted on the antibody sequences, frequency of use of genes, amino acid preferences, and the lengths of complementarity determining regions (CDR). Epitope hotspots for antibody binding were analyzed, and the spatial structural similarity of antibody paratopes was calculated and subjected to clustering, which allowed for a comprehensively exploration of the spatial recognition relationship between antigenic epitopes and antibodies. The specificity of antibodies targeting different antigenic epitope clusters was further validated through bio-layer interferometry (BLI) experiments. ResultsThe collected data revealed that the antigen-antibody complex structure data of influenza A virus NA protein in SAbDab database were mainly from H3N2, H7N9 and H1N1 subtypes. The hotspot regions of antigen epitopes were primarily located around the catalytic active site. The antibodies used for structural analysis were primarily derived from human and murine sources. Among murine antibodies, the most frequently used V-J gene combination was IGHV1-12*01/IGHJ2*01, while for human antibodies, the most common combination was IGHV1-69*01/IGHJ6*01. There were significant differences in the lengths and usage preferences of heavy chain CDR amino acids between antibodies that bind within the catalytic active site and those that bind to regions outside the catalytic active site. The results revealed that structurally similar antibodies could recognize the same epitopes, indicating a specific spatial recognition between antibody and antigen epitopes. Structural overlap in the binding regions was observed for antibodies with similar paratope structures, and the competitive binding of these antibodies to the epitope was confirmed through BLI experiments. ConclusionThe antigen epitopes of NA protein mainly ditributed around the catalytic active site and its surrounding loops. Spatial complementarity and electrostatic interactions play crucial roles in the recognition and binding of antibodies to antigenic epitopes in the catalytic region. There existed a spatial recognition relationship between antigens and antibodies that was independent of the uniqueness of antibody sequences, which means that antibodies with different sequences could potentially form similar local spatial structures and recognize the same epitopes.

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